The present invention relates generally to rotary solenoids, and more particularly, to a means for dampening vibrations resulting from the operation of such solenoids.
Various different types of solenoids have long been used to cause a mechanical movement responsive to an applied electrical signal. This can include longitudinal movements resulting from the reciprocation of a core (or slug) within a wound coil for receiving the applied electric signal. This can also include rotational movements of a shaft within a housing, responsive to reciprocation of the shaft within the wound coil. The present application is primarily directed to the latter of these two solenoid types.
While also present in solenoids with longitudinally moving cores, one disadvantage which often presents itself in connection with rotary solenoids is that of noise and vibration resulting from impacts between the internal components of the solenoid (or components of the driven load) upon reaching the end of their available travel.
Steps have been taken to address this problem, yet none have been entirely satisfactory. For example, it is possible to dampen vibrations of this general type by providing fixed stops having resilient surfaces which dampen impacts resulting from full travels of the solenoid (or the driven load). While this tends to reduce the amount of noise and impact forces which are produced, such measures can at times produce unacceptable bouncing of the solenoid's internal components (or components of the driven load) due to the resiliency of the stopper which is employed.
It therefore remained desirable to develop a damper for a rotary solenoid which is not only able to reduce unwanted noise and impact forces, but which is further able to reduce bouncing resulting from impacts of elements of the solenoid, or its associated driven load.